1. Field of the Invention
The present invention relates to an integrated-inverter electric compressor that is particularly suitable for use in an air-conditioning apparatus of a vehicle.
This application is based on Japanese Patent Application No. 2007-049868, the content of which is incorporated herein by reference.
2. Description of Related Art
Recently, the automobile industry has been rapidly promoting the development and commercialization of electrically driven vehicles, such as hybrid vehicles, electric vehicles, and fuel-cell-powered vehicles, to improve energy efficiency.
These vehicles employ air-conditioning apparatuses that, unlike conventional air-conditioning apparatuses, are provided with electric compressors driven by electrically powered motors.
These electric compressors are sealed electric compressors having a compressor and an electric motor in a housing and convert DC power from the power supply into three-phase AC power via an inverter device to supply the three-phase AC power to the electric motor so that the rotational speed of the compressor can be variably controlled according to the air-conditioning load.
For such an inverter-driven electric compressor, many integrated-inverter electric compressors that integrate inverter devices with housings thereof have been proposed.
An inverter device that has been proposed as the above-described integrated-inverter electric compressor has a structure in which six power MOS transistor modules (power semiconductor switching devices) constituting upper-arm switching devices and lower-arm switching devices for the three-phase inverter are disposed on a flat base surface of the outer circumferential surface of a motor housing; a printed-circuit board or the like, on which a plate with built-in busbars and an inverter control circuit are mounted, is disposed thereabove; and three terminals bent upward and extending from a side surface of each power MOS transistor module are fitted in connecting holes of the plate with built-in busbars by soldering (for example, see the Publication of Japanese Patent No. 3760887).
However, with the inverter device of the integrated-inverter electric compressor disclosed in the Publication of Japanese Patent No. 3760887, when assembling and mounting the power MOS transistor modules, the terminals bent upward and extending from the side surface thereof are easily misaligned. Because the number of terminals to be mounted is large (a total of 18 terminals are to be mounted, three terminals being mounted on each of the six power MOS transistor modules), assembly is difficult when fitting them in connecting holes provided in a plate with built-in busbar.
In addition, vertical vibrations are transmitted to the inverter device from the vehicle via the housing of the electric compressor. These vibrations are also transmitted to the power MOS transistor modules, and, in particular, when an excessive force due to these vibrations is applied to the terminals in the bending direction, the terminals may break, which is problematic in terms of vibration resistance.